Japanese Published Unexamined Utility Model Laid Open No. 1988 (S63)-147429 disclosed a typical large-sized synthetic resin bottle with a handle in which a handle and a bottle body are separately molded and joined together.
The conventional bottle comprises as follows. The bottle body is formed by biaxial oriented blow molding. During the blow molding, a recessed portion is vertically formed in an arc-like configuration at a rear portion of the bottle body, an engaging convexity extending in a vertical direction is formed in an arc-like configuration at the center of the recessed portion, grooves of which both ends are closed are vertically formed in an arc like configuration on the both side surfaces of the engaging convexity.
The handle comprises a pair of front frames formed in an arc-like configuration and a grip portion connecting the upper ends and the lower ends of the front frames and is formed by injection molding. During the injection molding, engaging projections are formed at the both sides of the front frames.
By strongly pushing the handle from the rear side to the recessed portion of the bottle body, the engaging projections of the handle are constrained to pass over engaging portions disposed on the tip of the engaging convexity so that the handle is joined to the bottle body not to be detachable.
The conventional technique as mentioned above has problems as follows.
Since the joint of the handle to the bottle body requires strong putting force, an equipment used for joining the handle to the bottle body is required, thereby increasing the production cost.
The thickness of the bottle body is thin because the bottle body is formed by biaxial oriented blow molding. Therefore, when the strong putting force is applied to the body to join the handle thereto, there is a possibility of irregular deformation such as buckling deformation of the bottle body by this force, thereby sometime producing a rejected article when joining the handle.
Since the thickness of the bottle body is thin because the bottle body is formed by biaxial oriented blow molding, it is easy to produce an elastic deflection by the load on the portion engaged with the handle. The joining force between the bottle body and a handle becomes weak due to the elastic deflection so that there is a possibility that the handle comes off the bottle body.
The joint of the handle to the bottle body is maintained only by the engagement of the engaging projections to the grooves, which is provided by that the engaging projections are constrained to pass over the engaging portions, so that it is easy to produce looseness on the joint between the bottle body and the handle. This causes the unstable handling of the bottle on grasp of the handle.
The bottle body and the handle are separately molded and the bottle body is formed by biaxial oriented blow molding while the handle is formed by injection molding, thereby dimensional accuracies between the bottle body and the handle are quite different from each other. Therefore, it is easy to produce looseness on the joint between the bottle body and the handle.
It is impossible to form the engaging portion of the bottle body sharp because of the biaxial oriented blow molding so that it is difficult to provide a strong and stable joint of the handle to the bottle body.
Because the recessed portion of the bottle body for joining the handle has a structure curved inwardly, the recessed portion is less durable against the loading applied to the bottle body during using than the other portion of the bottle body.
In particular, in state of heat filling of the content, the bottle body is slightly softened by the heat of the content so that the durability against the loading is relatively greatly weakened. Thereby, it is possibility of partial buckling at the recessed portion by the loading during using.
When the bottle body is used by gripping the handle in a state of filling the content in the bottle body, it is possibility of sinking deformation of the lower end portion of the recessed portion of the bottle body by that the lower end portion is applied with the load. It is impossible to repair the sinking deformation which is permanent, thereby turning to the poor-looking and deteriorating the value as goods.
For solving the problem of sinking deformation of the lower end portion of the recessed portion, there is a method for increasing the thickness of the bottle body. However, in this case, the synthetic resin material for forming the bottle body is increased so that the production cost becomes higher.
It should be noted that a synthetic resin bottle with a handle which has been devised by this applicant is disclosed in Japanese Utility Model Application No. 1992 (H4)-71484.
It is an object of the present invention to prevent the deformation of the engaging portion of the bottle body where is engaged with the handle, thereby providing the strong and stable joint between the bottle body and the handle.
It is an object of the present invention to prevent the joint at the bottle side where is engaged with the handle from producing the deflection while the bottle is loaded, thereby providing the strong and stable joint between the bottle body and the handle.
It is an object of the present invention to increase the strength at the recessed portion of the bottle body by joining the handle to the bottle body.
It is an object of the present invention to simplify the production steps of the synthetic resin bottle with a handle.